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Glycine (2-Aminoacetic Acid, Gly, G) is a conditionally essential amino acid and neurotransmitter. The simplest of all amino acids, glycine plays a role in the synthesis of nucleic acids, glutathione, RNA and DNA, and creatine.[i]
Glycine is synthesized in your body from threonine (through threonine dehydrogenase pathway), choline (via formation of sarcosine), and serine (through serine hydroxy methyltransferase [SHMT]).[ii]
Glycine is considered a “conditionally essential” amino acid because your body cannot produce enough on its own. So, the remainder must be obtained from foods like meat, fish, dairy, legumes, or supplements.[iii]
Glycine plays a critical role as a neurotransmitter because it controls your intake of food, behavior, and complete body homeostasis.
It can be both excitatory and inhibitory. Which means that it can stimulate your brain and nervous system, as well as quieten it.
Supplementing with glycine has been shown to effective in treating metabolic disorders, inflammatory disease, obesity, cancers, and diabetes.
Here we’ll investigate as a nootropic for enhancing sleep quality and brain function.
Glycine helps:
- Sleep: Glycine helps you fall asleep more quickly, reduce insomnia, improve sleep quality, and promote deeper and more restful sleep
- Neurological disorders: Glycine has been shown to be effective in those dealing with schizophrenia, OCD, and depression.
- Stroke: Patients who have suffered ischemic stroke (brain ischemia or cerebral ischemia), are given glycine orally to help limit damage to the brain within the first six hours of the stroke.
Overview
Glycine (2-Aminoacetic Acid, Gly, G) is one of the most important amino acids in your body. It helps in regulation of cardiovascular, cognitive, and metabolic health.
The name Glycine comes from the Greek word γλυκύς “sweet tasting“.
Glycine was discovered in 1829 by French chemist Henri Braconnot after boiling gelatin with sulphuric acid. And since then, it has been manufactured and distributed commercially as a sweetener, and as a buffering agent for antacids.
Glycine is also a sweet and colorless crystal that is synthesized in your body from choline, threonine, and serine.
As a therapeutic and nootropic supplement provides multiple benefits to human health.
Glycine has been shown to be effective for improving skin elasticity. And collagen peptide which is loaded with Glycine helps suppress sun-induced skin damage and reduce wrinkles around the eyes.[iv]
Glycine supplementation helps reduce the symptoms of schizophrenia.[v] It helps reduce symptoms of OCD. And low blood levels of glycine have been associated with depression.
Numerous studies have also shown glycine’s potential in improving sleep, enhancing memory, and increasing insulin sensitivity.
Glycine modulates inhibitory neurotransmitters via glycine receptors throughout the central nervous system.[vi] And potentiates NMDA receptors which provides an excitatory response.[vii] Affecting cognition, mood, immune function, and sleep.
How does Glycine work in the brain?
Glycine boosts brain health and function in several ways. But two in particular stand out.
- For sleep – Numerous studies have shown that glycine influences the quality of sleep, reduces insomnia, and promotes restful sleep. It does this in a couple of ways.
Glycine has a particular affinity for NMDA receptors and glycine receptors. Which results in increased peripheral blood flow, and a subsequent drop in the core body temperature.
In other words, glycine works to improve blood flow to the body’s extremities, which in turn reduces core body temperature.
This decrease in body temperature plays an important part of sleep induction since the onset of sleep is associated with lowered body temperature. Which then progresses to deep sleep.
Researchers demonstrated this in an animal study showing how glycine triggered a drop in body temperature which helped the study subjects fall asleep more quickly And spend more time in REM sleep. [viii]
The study also showed that glycine can help you experience deep, slow wave sleep more quickly.
Glycine has also been shown to increase the production of serotonin in the brain. Which helps sleep because serotonin aids in the synthesis of the sleep hormone melatonin.[ix]
Studies also suggest that glycine can help you get back to your regular sleep cycles after a period of a disrupted sleep schedule.[x]
- Schizophrenia – Glycine has shown promising results in reducing the symptoms of depression, OCD, anxiety, and bipolar disorder. However, its most pronounced efficacy is seen in the reduction of schizophrenia symptoms.
Post mortem evaluations of the brains of people with schizophrenia have shown fewer NMDA receptors compared to those who did not have the disease.
Researchers also found decreased levels of glycine in both the blood and cerebrospinal fluid of people with schizophrenia.[xi]
Glycine is known to be an NMDA agonist. It is well tolerated by the patients in both short-, and long-term treatment.
To date, numerous studies have been conducted to evaluate the efficacy of glycine in treating schizophrenia.
The first controlled trial used a glycine dose of 15 grams per day which showed significant improvement during glycine treatment.
Another study, 21 schizophrenic patients were given high doses of glycine in addition to antipsychotic treatment.
A significant 34% reduction in negative symptoms was observed during glycine treatment. And the study authors noted the improvement persisted even after patients stopped supplementing with glycine. [xii]
How things go bad
Sleep deprivation or the inability to get a good night’s sleep is an increasing concern world-wide. Not enough sleep or poor sleep quality can result in:
↓ Memory loss
↓ Inability to concentrate
↓ Poor metabolism
↑ Weight gain
↑ Irritability
↑ High blood pressure
↑ High blood sugar levels
↓ Low sex drive
↑ Risk of heart disease
Glycine as a nootropic supplement helps the body make serotonin which improves sleep and mood. And it influences key receptors in the brain resulting in better learning and memory.[xiii] [xiv]
Low glycine levels in the body are also linked to depression.[xv]
Glycine benefits
Glycine activates NMDA receptors in the brain and restores serotonin levels which helps improve sleep. And the ability to fall asleep faster.
In one study, 15 adult females were given either a placebo or 3 grams of glycine before bed.
The study concluded that supplementing with glycine showed a significant improvement in reduced fatigue, liveliness, and clear-headedness the next morning.[xvi]
Glycine helps brain cell signaling which boosts cognition, memory and mood.
Glycine taken in high doses has proven to be highly effective in reducing the symptoms of schizophrenia.
It helps with depression and mental fluency associated with schizophrenia.
And may improve psychotic symptoms as well.[xvii]
Evidence also suggests that glycine assists with depression and neurodegenerative diseases such as Alzheimer’s and Huntington’s.
Glycine also showed a protective effect against neurological damage associated with stroke.[xviii]
And research suggests improvements in memory, recall, and sustained attention in those supplementing with glycine as a nootropic.
How does Glycine feel?
People who take high quality glycine supplements report better sleep quality, and improved mood during the day.
Some users say they felt more balanced and livelier once they started supplementing with glycine.
Glycine is best taken 60 minutes before bed. Most users report a minimum of 7 hours of undisturbed, high quality sleep.
Glycine helps even chronic insomniacs fall asleep easily.
Unlike most sleep inducers, glycine does not leave you feeling groggy and fatigued in the morning. On the contrary, users wake up feeling rested and ready to tackle the day.
Glycine is a good joint health supplement. Because it aids in cartilage regeneration by enhancing collagen re-synthesis.
Glycine may also provide relief from night sweats for pre-menopausal and menopausal women.
Glycine Clinical Research
Glycine for schizophrenia
22 schizophrenic patients who were treatment-resistant took part in a double blind, placebo-controlled trial. They were administered 0.8g/kg per day of glycine along with their antipsychotic medication.
Clinical assessments were performed bi-weekly. The group who was administered glycine showed a 24-46% reduction in negative symptoms. [xix]
In another double-blind, placebo-controlled study, 14 medicated patients with chronic schizophrenia were treated with glycine. The results showed a significant improvement in negative symptoms in the group that was given glycine but not in the group given placebo. [xx]
Glycine for sleep
In a randomized placebo-controlled trial, 11 healthy adults were given either 3 grams of glycine or a placebo 1 hour before bed for 2 days. The results indicated quicker sleep onset followed by long, restful sleep.[xxi]
In 2012, another placebo-controlled study recruited healthy adults who were restricted to 25% less sleep than normal. Study subjects were given either a placebo or 3 grams of glycine before bed.
In subjects given glycine, the data showed a significant reduction in fatigue often related to reduced sleep.[xxii]
Glycine for learning and memory
Scientists studied the effects of bioglycin, a biologically active form of glycine in healthy students (mean age 20.7 years), and middle-aged men (mean age, 58.9 years).
The researchers specifically measured attention, memory, and mood using a double-blind, randomized design. [xxiii]
The results indicated that bioglycin significantly improved episodic memory in both the young and middle-aged group. And the middle-aged group also showed a significant improvement in the sustained-attention task.
Glycine Recommended Dosage
Recommended nootropic dosage of Glycine is 3 grams per day.
Experts recommend a Glycine dosage of 0.4 grams per kilogram of body weight (g/kg) twice daily when taking an atypical antipsychotic like Zyprexa and Risperdal.
Many human trials have safely used glycine doses of 1 g (1000 mg) per day for supporting brain health after a stroke. And up to 50 grams per day for schizophrenia.
Most Glycine supplements come in 1000 mg capsules. And the most effective dose is reported to be 3 grams 60 minutes before bed.
Glycine Side Effects
Glycine supplements are generally considered non-toxic and safe with few side effects in most people.
However, supplementing with 9 grams or more of Glycine may result in mild gastrointestinal symptoms such as an upset stomach, nausea, loose stools, or vomiting.
Slight sedation is also a possible side effect of taking glycine.
Do not take glycine if you are on the antipsychotic drug Clozaril (clozapine). Unlike other drugs used to treat schizophrenia, glycine appears to decrease the effectiveness of Clozaril in some people.[xxiv]
Do not use glycine if you are suffering from diarrhea, as it may worsen the condition.
Due to lack of sufficient research, glycine should be avoided by breastfeeding and pregnant women unless prescribed by a physician.
Type of Glycine to Buy
Glycine is available in 1000 mg capsules, 500 mg tablets, and as powder.
Look for a Glycine supplement with zero “other ingredients”.
Avoid Glycine supplements containing additives such as silicon dioxide, stearic acid, or magnesium stearate.
I recommend: Life Extension – Glycine because it is pure.
Nootropics Expert® Recommendation
I recommend Glycine as a nootropic supplement.
Your body makes some Glycine during the day. But you need more Glycine than your body can produce on its own. So, you must get it from food or a nootropic supplement.
Glycine is particularly effective in those dealing with sleep disorders or insomnia.
Supplementing with Glycine should provide a good night’s sleep. And have you feeling well-rested the next morning.
Glycine has been shown to be effective in those dealing with schizophrenia. Even while using most regular medications used with this disorder.
But please, if you are dealing with schizophrenia, check with your doctor before using this nootropic.
Glycine as a nootropic supplement used at recommended dosages is non-toxic and safe for most people with little or no side effects.
3 grams of Glycine seems to be most effective for most people taken about 60 minutes before bed.
I recommend: Life Extension – Glycine because it is pure.
Join The Discussion - 134 comments
MARIE
June 22, 2022
What is the difference between Glycine and L Glycine. I
Have read that ideally you need both
David Tomen
June 22, 2022
Marie, they are the same thing.
Danny O
February 22, 2022
Hello David, I take a powdered collagen peptide supplement daily, which includes 3.7g of Glycine. Is there any downside getting Glycine in this manner rather than a dedicated Glycine only supplement?
David Tomen
February 23, 2022
Danny, there is no downside that I am aware of.
Tony
February 22, 2022
Have you heard of glycine causing weight gain/water retention? I’ve been taking 1g a night for about a week and I’m usually very prone to anxiety and it’s definitely helped…almost too much to swinging into a little depression and lack of energy. I’m wondering if the glycine is causing an increase in creatine in the body as exogenous creatine, even at very low doses, causes severe water retention for me. It’s a shame because the glycine (dosing maybe dialed back a bit) is really helping, but the water retention makes it a ‘no go’. I’m not overweight but the retention is very much in the face. Thanks for having such a resourceful website!
David Tomen
February 23, 2022
Tony, it sounds like Glycine could be the wrong supplement for you. Water retention did not come up as a Side Effect in my research but each of us is unique in our chemical makeup. Something in your system is reacting to Glycine and causing this but I have no idea what it could be.
Andriana
June 19, 2022
I have the exact same issue! I feel like the glycine has tremendously helped my energy and stamina in daily life, and i take a fairly high dose like 9-12 grams per day, but I have too have noticed major water retention/puffiness in my face that I REALLY don’t like. I was thinking about seeing if there is an herb to help with water retention because in every other way I have felt my body respond very well to glycine. Curious if you ever found a solution to the problem.
David Tomen
June 19, 2022
Andriana, 9 – 12 grams of Glycine is a crazy high dose. 3 – 4-times the maximum recommended amount.
Borys
February 2, 2022
Hi David! I nearly always experience cold feet/hands when working from my home office, I don’t excersise. I only wander with my dog max 2 times per day. Could my brain fog be the cause of poor blood flow?
I take resveratrol, niacin, huperzine, Q10, zinc and gingko for blood flow
should I add more? Pine bark and Vinpocetine?
What do you think?
Thanks!
David Tomen
February 2, 2022
Borys, Vinpocetine and Pine Bark Extract are the most effective supplements for increasing blood brain blood flow that I know of. And poor cerebral blood flow can certainly cause brain fog.
But there are other causes of brain fog as well which I detail in this article: https://nootropicsexpert.com/best-supplements-for-brain-fog/
Andrew Richardson
January 28, 2022
If Tryptophan and Glycine are in Milk is it not better to have half a cup of warm milk before bed would this not give you what you need?
I’m already on Magnolia Bark 200MG and L-theanine 200MG my brain is stubborn to sleep maybe I am missing something? my Vit D level is normal so serotonin should not be an issue to make melatonin, not sure if adding glycine and Tryptophan would be better as a supplement or just sticking with the milk as I’ve been doing, which is more, effective. Thoughts?
David Tomen
January 29, 2022
Andrew, if you are already using milk and still have a problem with sleep maybe that is telling your something?
I suggest trying 500 mg L-Tryptophan and 1,000 mg Glycine and see if it helps. You can always go back to milk.
Andrew Richardson
January 29, 2022
I guess my question was more, do you get more out of a supplement than I would milk? should I be taking it an hour before bed as well
David Tomen
January 31, 2022
Andrew, many supplements are highly concentrated forms of what we normally get from food. The Tryptophan and Glycine you take as a supplement is going to be much more potent than what you would get from milk. To get the benefits for sleep it is best to take them 60 – 90 minutes before bed to give them time to digest and get into your system.
Adam
January 20, 2022
Greetings David!
Someone who suspect Anhedonia/ have problems with motivation and procrastination should inhibit NMDA receptors right? Choice is hard for me because some suplements inhibit NMDA like Huperzine while other enhance it (ex. glycine).
David Tomen
January 20, 2022
Adam, anhedonia is treated with NMDA receptor antagonists. And motivation is boosted by activating AMPA receptors.
Adam
January 21, 2022
Thank you David!
Is there any way I could find out my NMDA levels? How to know If I have to enhance or inhibit them?
Thanks!
David Tomen
January 21, 2022
Adam, there is no test for this at least that is available to the public. The only thing you can do is experiment with a couple of nootropics that affect NMDA receptors and see what happens.
Jurgen
October 21, 2021
Hi, I’ve read that you advice against using Glycine with magnesium stearate in it. I never checked my supplements for this but I have multiple supplements from the NOW brand and they seem to contain magnesium stearate. Can you explain me why that magnesium stearate is not adviced and any alternatives you recommend for my below NOW supplements?
NOW L-Tryptophan 1000mg tablets
NOW L-Tryptophan 500mg capsules
NOW DHA-500 softgels
NOW Sunflower Lecithin 1200mg softgels
David Tomen
October 27, 2021
Jurgen, magnesium stearate suppressed Killer T-Cells which are an important part of your immune system. You can read more about choosing high quality supplements in this article: https://nootropicsexpert.com/7-tips-for-choosing-the-highest-quality-nootropic-supplements/
This is the L-Tryptophan that I use: https://amzn.to/3GwjKVl
And this is the DHA supplement I use: https://bit.ly/3q98chL
And I do not recommend using Lecithin as a supplement.
Jurgen
October 28, 2021
Hi, why do you advice against taking Lecithin? What alternatives you recommend to get all those substances that are in Lecithin?
David Tomen
October 30, 2021
Jurgen, because it’s the Phosphatidylserine (PS) that is extracted from lecithin that your brain uses. Not the lecithin. There is no way to tell how much PS is in a particular lecithin supplement.
Jurgen
October 31, 2021
Ok, do I understand correctly that the only usefull substances in Lecithine are PS and PC, but that it is better to supplement those directly and never use Lecithin?
David Tomen
October 31, 2021
Jürgen, in my opinion that is your best option.
Yazan
July 26, 2021
Hi David,
Can I take Glycine with Performance Lab Sleep?
Thanks,
Yazan
David Tomen
July 28, 2021
Yazan, absolutely you can us Glycine with Performance Lab Sleep. I tested that for a few months and it worked well.
Yazan
July 28, 2021
Thanks!
Is it safe to take 3 grams of Glycine with Performance Lab Sleep?
David Tomen
July 29, 2021
Yes
Yazan
July 28, 2021
Thanks!